1. Field of Invention
The present disclosure relates in general to a system and method of well testing, and producing at multiple zones.
2. Description of Prior Art
Typically, when drilling an exploration well, a production type casing string is run and cemented above the target zone. After pressure tests of the cemented casing to ensure wellbore integrity, continued drilling is carried out into the target zone with carefully monitoring trip/connection gas together with surface mud logging to record penetrated formation lithology. Usually a decision is made to cut core samples when promising and potential reservoir rock types are encountered, afterwards continued drilling is carried out to well total depth, then wireline logs are run to identify porous/permeable zone and formation fluid types. If the formation evaluation from the above mentioned data acquisition (mud logging, wireline logs and core samples) indicates a potential reservoir, a barefoot well test is conducted subsequently to determine its economic potential. Post well test operation, if a decision is made to deepen the well to access deeper zone of interest, then a liner has to be run and cemented to isolate the tested zone (if hole size is allowed post liner installation). The whole process of formation evaluation in the deeper zone is repeated.
If a cased hole well test in the target zone is implemented due to concerns of well control risks, then to allow deepening of the well for exploring deep zones of interest, the perforated zones across the cased hole section have to be isolated and wellbore pressure integrity has to be ensured before proceeding to the next step. This may be achieved by squeezing perforated zones with cement, if unsuccessful with restoring wellbore integrity, a casing patch or liner has to be run (if post installation hole size is sufficient), in some cases a sidetrack operation from the above tested zone may be conducted, consequently a large amount of rig operating time and associated cost incur unavoidably before even reaching the planned secondary target zone.